Out-of-hospital cardiac arrest (OHCA) is a major cause of death in the United States, affecting approximately 300,000 citizens annually. The optimal management of patients with OHCA involves a total population health approach that engages the public health system (access to automatic external defibrillators), out-of-hospital care (prompt response of emergency medical services, clear destination protocols to take patients to cardiac resuscitation centers), and in-hospital care (rapid access to high volume cardiac catheterization, hypothermia induction protocols). Marked geographic variability exists in the management and outcomes of OHCA, and leading professional societies have supported the development of cardiac arrest systems of care. The Institute of Medicine (IOM) recently defined total population health as the health of all persons living in a specified geopolitical area, and challenged the public health and healthcare communities to work collaboratively to improve the health of the population. In this proposal, we describe a plan to develop new spatial methods that will align incentives for the many stakeholders involved in the management of patients with OHCA. Our work will be achieved in three aims: Aim 1. Describe the existing patterns of hospital utilization for patients with OHCA. In this aim we will use geocoded claims data from the Centers for Medicare & Medicaid Services to measure the geographic flow of patients to hospitals. Aim 2. Identify empirically existing cardiac arrest hospital coalitions and their geographic catchment areas (cardiac arrest service areas). In this aim, we will use spatial cluster analysis to define empirically occurring clusters of hospitals based on overlapping patient utilization patterns, identify an optimal clustering solution (a coalition), and determine the corresponding geographic catchment area for each coalition (a cardiac arrest service area). Aim 3. Determine variability in risk-adjusted survival across cardiac arrest service areas. In our fina aim, we will develop and calibrate risk adjustment models to compare outcomes across cardiac arrest service areas. We will explore the relative importance of factors at the individual, community, public health, out-of-hospital, and in-hospital level on OHCA and will benchmark outcomes across cardiac arrest service areas. This work has the ability to fundamentally alter the management of OHCA, through facilitating the development of cardiac arrest systems of care by aligning incentives across multiple stakeholders within a unified accountable unit of care. Our methods are replicable, scalable, and consistent with the IOM's vision of total population health and the American Heart Association's efforts to build regional systems of care for OHCA.